They probably don't use the term 'guessing".
From the Federal Reserve Bank Of Cleveland, updated through April 28:
Inflation, month-over-month percent change
Month CPI Core CPI PCE Core PCE Updated
April 2025 0.23 0.23 0.20 0.21 04/28
March 2025 -0.00 0.10 04/28
Note: If the cell is blank, it implies that the actual data corresponding to the month for that inflation measure have already been released.
Which, combined with the March 2024 figure dropping off, brings their guess for year-over-year percentage change in the personal consumption expenditures deflator to 2.19%.
Inflation, year-over-year percent change
Month CPI Core CPI PCE Core PCE Updated
April 2025 2.35 2.76 2.12 2.50 04/28
March 2025 2.19 2.54 04/28
Note: If the cell is blank, it implies that the actual data corresponding to the month for that inflation measure have already been released.
...MORE
So, we shall see, 8:30 10:00 am, EDT.
Correction: someone (ahem) used the GDP release time rather than the PCE release time.
See also April 28's "The Basic Laws of Human Stupidity".